2.2.3 In festival subdirectory

If –with-module is not yes, the whole src subtree needs not to be installed. In this sort of situations, we do not let ede calculating the SUBDIRS Makefile variable but force it to a given value

      @ac_cv_pln_package_festival_subdirs@

that should be calculated at m4 level according to the –with-plugin/module value.

In plugin case only lib should be made since in module case, src, lib, m4, config should be made. Moreover the modconf.sh action is not the same.